Concurrent object—oriented systems differ from traditional concurrent sys terns(e．g．systems being described by CSP or CCS)in that the process topologies of them are usually dynamic，and the inter—process communication links among processes are cre-ated or withdrawn accordinglywith the change of objects．Graph grammar turns out to be aformal tOOl much more suitable than other formalisms to specify such kink of concurrency and dynamic characteristics．This paper introduces a new graph grammar model for speci-lying concurrent object—oriented systems．System developers can specify both the static and dynamic structures of their concurrent object— oriented systems using the CSDL lan- guage provided by our model．Via a development and supporting environment for concur-rent object—oriented systems(GRADECS)，the CSDL specification of concurrent system structure can be transformed to run time process topologies，and the CSDL specification of dependence and communication relations among system components can be dynamically bound to inter—process communication links for message passing．